Trying and Trying but feel too old and too stressed

My partner and I have been ttc for just over 2 1/2 yrs now, we've been together since Jan 02. We met late in our lives. I wouldn't mind so much but time is of the essence, I am 41 1/2 and he is 40. We have no children between us. We are trying to cope but with everyone around us, my sisters both have babies, my brother has two one born in Dec, his sister is in delivery with TWINS today (31 July 07), his brother had a baby a year ago. So as you can see 4 babies in 1 year makes it all the more harrowing for us. We try to be strong but inside we are weak. I have PCOS, Endometriosis and Type II Diabetes. I lost a pregnancy at 11 wks in Dec 05. I didn't even know I was pregnant! We've consulted here in UK for IVF but are struggling with the financial cost of it all. How do we cope???? How do we achieve this goal in life without it causing us so much stress? How do we put on a happy face for everyone else around us?